--- /dev/null
+<?php // $Id$
+
+/* PHP lexer code snarfed from the CVS tree for the lamplib project at
+ * http://sourceforge.net/projects/lamplib
+ * This project is administered by Markus Baker, Harry Fuecks and Matt
+ * Mitchell, and the project code is in the public domain.
+ *
+ * Thanks, guys!
+ */
+
+ define("LEXER_ENTER", 1);
+ define("LEXER_MATCHED", 2);
+ define("LEXER_UNMATCHED", 3);
+ define("LEXER_EXIT", 4);
+ define("LEXER_SPECIAL", 5);
+
+ /**
+ * Compounded regular expression. Any of
+ * the contained patterns could match and
+ * when one does it's label is returned.
+ */
+ class ParallelRegex {
+ var $_patterns;
+ var $_labels;
+ var $_regex;
+ var $_case;
+
+ /**
+ * Constructor. Starts with no patterns.
+ * @param $case True for case sensitive, false
+ * for insensitive.
+ * @public
+ */
+ function ParallelRegex($case) {
+ $this->_case = $case;
+ $this->_patterns = array();
+ $this->_labels = array();
+ $this->_regex = null;
+ }
+
+ /**
+ * Adds a pattern with an optional label.
+ * @param $pattern Perl style regex, but ( and )
+ * lose the usual meaning.
+ * @param $label Label of regex to be returned
+ * on a match.
+ * @public
+ */
+ function addPattern($pattern, $label = true) {
+ $count = count($this->_patterns);
+ $this->_patterns[$count] = $pattern;
+ $this->_labels[$count] = $label;
+ $this->_regex = null;
+ }
+
+ /**
+ * Attempts to match all patterns at once against
+ * a string.
+ * @param $subject String to match against.
+ * @param $match First matched portion of
+ * subject.
+ * @return True on success.
+ * @public
+ */
+ function match($subject, &$match) {
+ if (count($this->_patterns) == 0) {
+ return false;
+ }
+ if (!preg_match($this->_getCompoundedRegex(), $subject, $matches)) {
+ $match = "";
+ return false;
+ }
+ $match = $matches[0];
+ for ($i = 1; $i < count($matches); $i++) {
+ if ($matches[$i]) {
+ return $this->_labels[$i - 1];
+ }
+ }
+ return true;
+ }
+
+ /**
+ * Compounds the patterns into a single
+ * regular expression separated with the
+ * "or" operator. Caches the regex.
+ * Will automatically escape (, ) and / tokens.
+ * @param $patterns List of patterns in order.
+ * @private
+ */
+ function _getCompoundedRegex() {
+ if ($this->_regex == null) {
+ for ($i = 0; $i < count($this->_patterns); $i++) {
+ $this->_patterns[$i] = '(' . str_replace(
+ array('/', '(', ')'),
+ array('\/', '\(', '\)'),
+ $this->_patterns[$i]) . ')';
+ }
+ $this->_regex = "/" . implode("|", $this->_patterns) . "/" . $this->_getPerlMatchingFlags();
+ }
+ return $this->_regex;
+ }
+
+ /**
+ * Accessor for perl regex mode flags to use.
+ * @return Flags as string.
+ * @private
+ */
+ function _getPerlMatchingFlags() {
+ return ($this->_case ? "msS" : "msSi");
+ }
+ }
+
+ /**
+ * States for a stack machine.
+ */
+ class StateStack {
+ var $_stack;
+
+ /**
+ * Constructor. Starts in named state.
+ * @param $start Starting state name.
+ * @public
+ */
+ function StateStack($start) {
+ $this->_stack = array($start);
+ }
+
+ /**
+ * Accessor for current state.
+ * @return State as string.
+ * @public
+ */
+ function getCurrent() {
+ return $this->_stack[count($this->_stack) - 1];
+ }
+
+ /**
+ * Adds a state to the stack and sets it
+ * to be the current state.
+ * @param $state New state.
+ * @public
+ */
+ function enter($state) {
+ array_push($this->_stack, $state);
+ }
+
+ /**
+ * Leaves the current state and reverts
+ * to the previous one.
+ * @return False if we drop off
+ * the bottom of the list.
+ * @public
+ */
+ function leave() {
+ if (count($this->_stack) == 1) {
+ return false;
+ }
+ array_pop($this->_stack);
+ return true;
+ }
+ }
+
+ /**
+ * Accepts text and breaks it into tokens.
+ * Some optimisation to make the sure the
+ * content is only scanned by the PHP regex
+ * parser once. Lexer modes must not start
+ * with leading underscores.
+ */
+ class Lexer {
+ var $_regexes;
+ var $_parser;
+ var $_mode;
+ var $_mode_handlers;
+ var $_case;
+
+ /**
+ * Sets up the lexer in case insensitive matching
+ * by default.
+ * @param $parser Handling strategy by
+ * reference.
+ * @param $start Starting handler.
+ * @param $case True for case sensitive.
+ * @public
+ */
+ function Lexer(&$parser, $start = "accept", $case = false) {
+ $this->_case = $case;
+ $this->_regexes = array();
+ $this->_parser = &$parser;
+ $this->_mode = new StateStack($start);
+ $this->_mode_handlers = array();
+ }
+
+ /**
+ * Adds a token search pattern for a particular
+ * parsing mode. The pattern does not change the
+ * current mode.
+ * @param $pattern Perl style regex, but ( and )
+ * lose the usual meaning.
+ * @param $mode Should only apply this
+ * pattern when dealing with
+ * this type of input.
+ * @public
+ */
+ function addPattern($pattern, $mode = "accept") {
+ if (!isset($this->_regexes[$mode])) {
+ $this->_regexes[$mode] = new ParallelRegex($this->_case);
+ }
+ $this->_regexes[$mode]->addPattern($pattern);
+ }
+
+ /**
+ * Adds a pattern that will enter a new parsing
+ * mode. Useful for entering parenthesis, strings,
+ * tags, etc.
+ * @param $pattern Perl style regex, but ( and )
+ * lose the usual meaning.
+ * @param $mode Should only apply this
+ * pattern when dealing with
+ * this type of input.
+ * @param $new_mode Change parsing to this new
+ * nested mode.
+ * @public
+ */
+ function addEntryPattern($pattern, $mode, $new_mode) {
+ if (!isset($this->_regexes[$mode])) {
+ $this->_regexes[$mode] = new ParallelRegex($this->_case);
+ }
+ $this->_regexes[$mode]->addPattern($pattern, $new_mode);
+ }
+
+ /**
+ * Adds a pattern that will exit the current mode
+ * and re-enter the previous one.
+ * @param $pattern Perl style regex, but ( and )
+ * lose the usual meaning.
+ * @param $mode Mode to leave.
+ * @public
+ */
+ function addExitPattern($pattern, $mode) {
+ if (!isset($this->_regexes[$mode])) {
+ $this->_regexes[$mode] = new ParallelRegex($this->_case);
+ }
+ $this->_regexes[$mode]->addPattern($pattern, "__exit");
+ }
+
+ /**
+ * Adds a pattern that has a special mode.
+ * Acts as an entry and exit pattern in one go.
+ * @param $pattern Perl style regex, but ( and )
+ * lose the usual meaning.
+ * @param $mode Should only apply this
+ * pattern when dealing with
+ * this type of input.
+ * @param $special Use this mode for this one token.
+ * @public
+ */
+ function addSpecialPattern($pattern, $mode, $special) {
+ if (!isset($this->_regexes[$mode])) {
+ $this->_regexes[$mode] = new ParallelRegex($this->_case);
+ }
+ $this->_regexes[$mode]->addPattern($pattern, "_$special");
+ }
+
+ /**
+ * Adds a mapping from a mode to another handler.
+ * @param $mode Mode to be remapped.
+ * @param $handler New target handler.
+ * @public
+ */
+ function mapHandler($mode, $handler) {
+ $this->_mode_handlers[$mode] = $handler;
+ }
+
+ /**
+ * Splits the page text into tokens. Will fail
+ * if the handlers report an error or if no
+ * content is consumed. If successful then each
+ * unparsed and parsed token invokes a call to the
+ * held listener.
+ * @param $raw Raw HTML text.
+ * @return True on success, else false.
+ * @public
+ */
+ function parse($raw) {
+ if (!isset($this->_parser)) {
+ return false;
+ }
+ $length = strlen($raw);
+ while (is_array($parsed = $this->_reduce($raw))) {
+ list($unmatched, $matched, $mode) = $parsed;
+ if (!$this->_dispatchTokens($unmatched, $matched, $mode)) {
+ return false;
+ }
+ if (strlen($raw) == $length) {
+ return false;
+ }
+ $length = strlen($raw);
+ }
+ if (!$parsed) {
+ return false;
+ }
+ return $this->_invokeParser($raw, LEXER_UNMATCHED);
+ }
+
+ /**
+ * Sends the matched token and any leading unmatched
+ * text to the parser changing the lexer to a new
+ * mode if one is listed.
+ * @param $unmatched Unmatched leading portion.
+ * @param $matched Actual token match.
+ * @param $mode Mode after match. The "_exit"
+ * mode causes a stack pop. An
+ * false mode causes no change.
+ * @return False if there was any error
+ * from the parser.
+ * @private
+ */
+ function _dispatchTokens($unmatched, $matched, $mode = false) {
+ if (!$this->_invokeParser($unmatched, LEXER_UNMATCHED)) {
+ return false;
+ }
+ if ($mode === "__exit") {
+ if (!$this->_invokeParser($matched, LEXER_EXIT)) {
+ return false;
+ }
+ return $this->_mode->leave();
+ }
+ if (strncmp($mode, "_", 1) == 0) {
+ $mode = substr($mode, 1);
+ $this->_mode->enter($mode);
+ if (!$this->_invokeParser($matched, LEXER_SPECIAL)) {
+ return false;
+ }
+ return $this->_mode->leave();
+ }
+ if (is_string($mode)) {
+ $this->_mode->enter($mode);
+ return $this->_invokeParser($matched, LEXER_ENTER);
+ }
+ return $this->_invokeParser($matched, LEXER_MATCHED);
+ }
+
+ /**
+ * Calls the parser method named after the current
+ * mode. Empty content will be ignored.
+ * @param $content Text parsed.
+ * @param $is_match Token is recognised rather
+ * than unparsed data.
+ * @private
+ */
+ function _invokeParser($content, $is_match) {
+ if (($content === "") || ($content === false)) {
+ return true;
+ }
+ $handler = $this->_mode->getCurrent();
+ if (isset($this->_mode_handlers[$handler])) {
+ $handler = $this->_mode_handlers[$handler];
+ }
+ return $this->_parser->$handler($content, $is_match);
+ }
+
+ /**
+ * Tries to match a chunk of text and if successful
+ * removes the recognised chunk and any leading
+ * unparsed data. Empty strings will not be matched.
+ * @param $raw The subject to parse. This is the
+ * content that will be eaten.
+ * @return Three item list of unparsed
+ * content followed by the
+ * recognised token and finally the
+ * action the parser is to take.
+ * True if no match, false if there
+ * is a parsing error.
+ * @private
+ */
+ function _reduce(&$raw) {
+ if (!isset($this->_regexes[$this->_mode->getCurrent()])) {
+ return false;
+ }
+ if ($raw === "") {
+ return true;
+ }
+ if ($action = $this->_regexes[$this->_mode->getCurrent()]->match($raw, $match)) {
+ $count = strpos($raw, $match);
+ $unparsed = substr($raw, 0, $count);
+ $raw = substr($raw, $count + strlen($match));
+ return array($unparsed, $match, $action);
+ }
+ return true;
+ }
+ }
+?>
--- /dev/null
+<?php // $Id$
+
+require_once($CFG->libdir.'/lexer.php');
+
+// Constants for the various types of tokens
+
+define("T_USER","0");
+define("T_META","1");
+define("T_EXACT","2");
+define("T_NEGATE","3");
+define("T_STRING","4");
+
+// Class to hold token/value pairs after they're parsed.
+
+class search_token {
+ var $value;
+ var $type;
+ function search_token($type,$value){
+ $this->type = $type;
+ $this->value = $this->sanitize($value);
+
+ }
+
+ // Try to clean up user input to avoid potential security issues.
+ // Need to think about this some more.
+
+ function sanitize($userstring){
+ return htmlentities(addslashes($userstring));
+ }
+ function getValue(){
+ return $this->value;
+ }
+ function getType(){
+ return $this->type;
+ }
+}
+
+
+
+// This class does the heavy lifting of lexing the search string into tokens.
+// Using a full-blown lexer is probably overkill for this application, but
+// might be useful for other tasks.
+
+class search_lexer extends Lexer{
+
+ function search_lexer($parser){
+
+ // Call parent constructor.
+ $this->Lexer($parser);
+
+ //Set up the state machine and pattern matches for transitions.
+
+ // Patterns to handle strings of the form user:foo
+
+ // If we see the string user: while in the base accept state, start
+ // parsing a username and go to the inusername state.
+ $this->addEntryPattern("user:\S+","accept","inusername");
+
+ // Snarf everything into the username until we see whitespace, then exit
+ // back to the base accept state.
+ $this->addExitPattern("\s","inusername");
+
+ // Patterns to handle strings of the form meta:foo
+
+ // If we see the string meta: while in the base accept state, start
+ // parsing a username and go to the inmeta state.
+ $this->addEntryPattern("subject:\S+","accept","inmeta");
+
+ // Snarf everything into the meta token until we see whitespace, then exit
+ // back to the base accept state.
+ $this->addExitPattern("\s","inmeta");
+
+
+ // Patterns to handle required exact match strings (+foo) .
+
+ // If we see a + sign while in the base accept state, start
+ // parsing an exact match string and enter the inrequired state
+ $this->addEntryPattern("\+\S+","accept","inrequired");
+ // When we see white space, exit back to accept state.
+ $this->addExitPattern("\s","inrequired");
+
+ // Handle excluded strings (-foo)
+
+ // If we see a - sign while in the base accept state, start
+ // parsing an excluded string and enter the inexcluded state
+ $this->addEntryPattern("\-\S+","accept","inexcluded");
+ // When we see white space, exit back to accept state.
+ $this->addExitPattern("\s","inexcluded");
+
+
+ // Patterns to handle quoted strings.
+
+ // If we see a quote while in the base accept state, start
+ // parsing a quoted string and enter the inquotedstring state.
+ // Grab everything until we see the closing quote.
+
+ $this->addEntryPattern("\"[^\"]+","accept","inquotedstring");
+
+ // When we see a closing quote, reenter the base accept state.
+ $this->addExitPattern("\"","inquotedstring");
+
+ // Patterns to handle ordinary, nonquoted words.
+
+ // When we see non-whitespace, snarf everything into the nonquoted word
+ // until we see whitespace again.
+ $this->addEntryPattern("\S+","accept","plainstring");
+
+ // Once we see whitespace, reenter the base accept state.
+ $this->addExitPattern("\s","plainstring");
+
+ }
+}
+
+
+
+
+// This class takes care of sticking the proper token type/value pairs into
+// the parsed token array.
+// Most functions in this class should only be called by the lexer, the
+// one exception being getParseArray() which returns the result.
+
+class search_parser {
+ var $tokens;
+
+
+ // This function is called by the code that's interested in the result of the parse operation.
+ function get_parsed_array(){
+ return $this->tokens;
+ }
+
+ /*
+ * Functions below this are part of the state machine for the parse
+ * operation and should not be called directly.
+ */
+
+ // Base state. No output emitted.
+ function accept() {
+ return true;
+ }
+
+
+ // State for handling user:foo constructs. Potentially emits a token.
+ function inusername($content){
+ if(strlen($content) < 6) // State exit or missing parameter.
+ return true;
+ // Strip off the user: part and add the reminder to the parsed token array
+ $param = trim(substr($content,5));
+ $this->tokens[] = new search_token(T_USER,$param);
+ return true;
+ }
+
+
+ // State for handling meta:foo constructs. Potentially emits a token.
+ function inmeta($content){
+ if(strlen($content) < 9) // Missing parameter.
+ return true;
+ // Strip off the meta: part and add the reminder to the parsed token array.
+ $param = trim(substr($content,8));
+ $this->tokens[] = new search_token(T_META,$param);
+ return true;
+ }
+
+
+ // State entered when we've seen a required string (+foo). Potentially
+ // emits a token.
+ function inrequired($content){
+ if(strlen($content) < 2) // State exit or missing parameter, don't emit.
+ return true;
+ // Strip off the + sign and add the reminder to the parsed token array.
+ $this->tokens[] = new search_token(T_EXACT,substr($content,1));
+ return true;
+ }
+
+ // State entered when we've seen an excluded string (-foo). Potentially
+ // emits a token.
+ function inexcluded($content){
+ if(strlen($content) < 2) // State exit or missing parameter.
+ return true;
+ // Strip off the -sign and add the reminder to the parsed token array.
+ $this->tokens[] = new search_token(T_NEGATE,substr($content,1));
+ return true;
+ }
+
+
+ // State entered when we've seen a quoted string. Potentially emits a token.
+ function inquotedstring($content){
+ if(strlen($content) < 2) // State exit or missing parameter.
+ return true;
+ // Strip off the opening quote and add the reminder to the parsed token array.
+ $this->tokens[] = new search_token(T_STRING,substr($content,1));
+ return true;
+ }
+
+ // State entered when we've seen an ordinary, non-quoted word. Potentially
+ // emits a token.
+ function plainstring($content){
+ if(ctype_space($content)) // State exit
+ return true;
+ // Add the string to the parsed token array.
+ $this->tokens[] = new search_token(T_STRING,$content);
+ return true;
+ }
+
+
+
+}
+
+
+// Primitive function to generate a SQL string from a parse tree.
+// Parameters:
+//
+// $parsetree should be a parse tree generated by a
+// search_lexer/search_parser combination.
+// Other fields are database table names to search.
+
+function search_generate_SQL($parsetree,$datafield,$metafield,$mainidfield,$useridfield,$userfirstnamefield,$userlastnamefield){
+ global $CFG;
+ if ($CFG->dbtype == "postgres7") {
+ $LIKE = "ILIKE"; // case-insensitive
+ $NOTLIKE = "NOT ILIKE"; // case-insensitive
+ $REGEXP = "~*";
+ $NOTREGEXP = "!~*";
+ } else {
+ $LIKE = "LIKE";
+ $NOTLIKE = "NOT LIKE";
+ $REGEXP = "REGEXP";
+ $NOTREGEXP = "NOT REGEXP";
+ }
+
+ $ntokens = count($parsetree);
+ if($ntokens == 0)
+ return "";
+
+ for($i = 0; $i < $ntokens; $i++){
+ if($i > 0) // We have more than one clause, need to tack on AND
+ $SQLString .= " AND ";
+
+ $type = $parsetree[$i]->getType();
+ $value = $parsetree[$i]->getValue();
+ switch($type){
+ case T_STRING : $SQLString .= "(($datafield $LIKE '%$value%') OR ($metafield $LIKE '%$value%') )";
+ break;
+ case T_EXACT:
+ $SQLString .= "(($datafield $REGEXP '[[:<:]]".$value."[[:>:]]') OR ($metafield $REGEXP '[[:<:]]".$value."[[:>:]]'))";
+ break;
+ case T_META : if($metafield != "")
+ $SQLString .= "($metafield $LIKE '%$value%')";
+ break;
+ case T_USER : $SQLString .= "(($mainidfield = $useridfield) AND (($userfirstnamefield $LIKE '%$value%') OR ($userlastnamefield $LIKE '%$value%')))";
+ break;
+ case T_NEGATE: $SQLString .= "(NOT (($datafield $LIKE '%$value%') OR ($metafield $LIKE '%$value%')))";
+ break;
+ default:
+ return "";
+
+ }
+ }
+ return $SQLString;
+}
+
+
+?>
projects / moodle.git / commitdiff